Why are highly processed foods unhealthy? A Comprehensive Look at the Risks

January 9, 2026 •

4 min read

Statistics show that highly processed foods can account for nearly 60% of U.S. adults' total calorie consumption, with this figure being even higher for children. So, why are highly processed foods unhealthy and what makes them so detrimental to our well-being and long-term health?

Quick Summary

Industrially formulated foods, rich in fat, sugar, and sodium, are stripped of vital nutrients and loaded with artificial additives. These products promote overconsumption and disrupt gut health, increasing the risk of obesity, inflammation, and chronic diseases like diabetes and heart issues.

Key Points

Nutrient Depletion: Highly processed foods are stripped of natural fiber, vitamins, and minerals during manufacturing, leaving them nutritionally deficient.
High in Unhealthy Additives: They contain industrial additives like emulsifiers and flavorings that can disrupt the gut microbiome and trigger inflammation.
Excessive Unhealthy Components: UPFs are formulated with high levels of added sugar, salt, and saturated fats to enhance flavor, which are linked to various chronic diseases.
Encourages Overconsumption: These foods are often hyper-palatable and less satiating than whole foods, leading to increased calorie intake and potential weight gain.
Increased Disease Risk: A diet rich in UPFs is strongly associated with higher risks of obesity, type 2 diabetes, cardiovascular disease, and certain cancers.
Negative Gut and Mental Health Effects: The imbalance in the gut microbiome caused by UPFs is linked to chronic inflammation and a potential negative impact on mental health.

The Hidden Dangers of Ultra-Processed Foods

Ultra-processed foods (UPFs), distinct from minimally processed items like frozen vegetables or canned beans, are industrial formulations often containing five or more ingredients. These ingredients frequently include substances not used in traditional home cooking, such as preservatives, emulsifiers, flavorings, and sweeteners, all designed to create a hyper-palatable, convenient, and long-lasting product. While their appeal is undeniable, the extensive industrial process and the final composition of these foods contribute to significant negative health outcomes.

Nutrient Stripping and Nutrient Deficiency

One of the primary issues with UPFs is what is removed, not just what is added. The industrial refining process typically strips foods of their natural fiber, vitamins, and minerals. Whole grains are processed into refined flours, and fruits are turned into sugary drinks, leaving behind what many nutritionists call “empty calories”. This nutritional void is a critical factor in why highly processed foods are unhealthy. The low fiber content in particular is detrimental, as it starves the beneficial microbes in the gut, disrupting the gut microbiome and increasing inflammation.

The Impact of Excessive Additives

Beyond just the main ingredients, UPFs are packed with cosmetic additives to enhance their sensory appeal and increase shelf life. These can include artificial sweeteners, colors, and emulsifiers. Research has shown that these additives can negatively impact gut health by disrupting the delicate balance of the gut microbiome. For example, studies have indicated that certain emulsifiers can weaken the intestinal barrier, increasing susceptibility to inflammation. The long-term effects of consuming a “cocktail” of various additives are still being studied, but current evidence suggests a strong link to chronic inflammatory diseases.

High Levels of Added Sugar, Sodium, and Unhealthy Fats

The industrial formulation of UPFs focuses heavily on creating products that are intensely appealing to the palate, which is often achieved by adding excessive amounts of sugar, salt, and fat.

Added Sugar: UPFs contribute almost 90% of the added sugars in the average American diet. These sugars, distinct from naturally occurring ones in fruits and dairy, cause rapid blood glucose spikes and are linked to obesity, diabetes, and heart disease.
Sodium: The average daily salt intake in many countries far exceeds recommendations, with a large portion coming from UPFs like ready meals, processed meats, and snacks. High sodium intake is a major contributor to high blood pressure and increased risk of cardiovascular disease.
Unhealthy Fats: UPFs often contain high amounts of saturated and sometimes trans fats (though mostly banned), including inexpensive tropical oils like palm and coconut oil. These fats raise LDL (bad) cholesterol, increasing the risk of heart disease.

The Health Risks of a High-Processed Food Diet

Consumption of a diet dominated by ultra-processed foods is associated with a wide range of negative health outcomes.

Obesity and Overconsumption

A 2019 NIH study demonstrated that when participants were on a highly processed diet, they consumed an average of 500 calories more per day and gained weight, compared to when they ate a minimally processed diet. UPFs are less satiating, meaning they do not provide the same feeling of fullness as whole foods, leading people to eat more. Their hyper-palatability, carefully engineered through combinations of fat, sugar, and salt, makes them easy to overeat and potentially habit-forming.

Gut Health Disruption and Inflammation

The lack of fiber and presence of additives in UPFs can lead to an imbalanced gut microbiome, a condition known as dysbiosis. This fosters a pro-inflammatory environment, reducing microbial diversity and increasing gut permeability. This chronic, low-grade inflammation is linked to numerous chronic diseases, including inflammatory bowel disease (IBD) and cardiometabolic diseases.

Increased Risk of Chronic Disease

Extensive research has linked high UPF consumption to a greater incidence of chronic diseases, including:

Cardiovascular Disease and Stroke: Studies show a clear association between higher UPF intake and increased cardiovascular risk. The high content of saturated fat and sodium is a major contributing factor.
Type 2 Diabetes: The high sugar content and rapid absorption characteristic of UPFs contribute to blood sugar dysregulation, increasing the risk of type 2 diabetes.
Certain Cancers: Research suggests a link between high UPF consumption and an increased risk of certain cancers, particularly bowel cancer.
Mental Health Issues: Emerging studies indicate that diets high in UPFs may be associated with a higher risk of depression, anxiety, and even cognitive decline, potentially through inflammation and gut-brain axis dysfunction.

Whole Foods vs. Highly Processed Foods: A Comparison

To understand the contrast, it's helpful to compare the two food types directly.


Feature	Whole Foods (e.g., Apple)	Highly Processed Food (e.g., Apple-flavored snack)
Nutrient Density	High; rich in natural fiber, vitamins, and minerals.	Low; essential nutrients are often stripped during processing.
Fiber Content	High; promotes digestion and gut health.	Low; can disrupt the gut microbiome.
Satiety	High; natural fiber and bulk promote a feeling of fullness.	Low; engineered to be hyper-palatable, encouraging overconsumption.
Added Ingredients	None, or minimally processed (e.g., dried fruit with no added sugar).	Many; including added sugars, unhealthy fats, sodium, emulsifiers, and artificial flavors.
Health Impact	Associated with a lower risk of chronic diseases.	Linked to increased risk of obesity, inflammation, and chronic illness.

Conclusion

The extensive industrial processing of highly processed foods, coupled with their specific ingredient profiles, makes them fundamentally unhealthy. The combination of stripped nutrients, high levels of added sugar, unhealthy fats, and sodium, and the inclusion of additives contributes to a wide range of negative health outcomes, from obesity and inflammation to chronic diseases like heart disease and diabetes. By prioritizing a diet rich in whole, minimally processed foods, and limiting UPF intake, individuals can make a profound positive impact on their long-term health and well-being. For more information on building a balanced diet, consult resources like the WHO's healthy diet fact sheet.

Frequently Asked Questions

Minimally processed food, like frozen vegetables or canned beans, retains most of its original nutritional value. Highly or ultra-processed food is an industrial formulation with many additives, often high in sugar, fat, and salt, and low in nutrients.

Highly processed foods negatively impact gut health by disrupting the gut microbiome. Their low fiber content starves beneficial gut bacteria, while certain additives can cause an imbalance and increase inflammation.

Yes. Studies show that highly processed foods are less satiating, causing people to consume more calories. Their hyper-palatable nature also encourages overeating, leading to weight gain.

No, not all processed foods are unhealthy. Many minimally processed foods, such as wholemeal bread or baked beans, can be part of a healthy diet. The issue lies primarily with ultra-processed foods that have undergone extensive industrial processing.

Yes. The high levels of added sodium and unhealthy saturated fats in many highly processed foods contribute to high blood pressure and elevated cholesterol, which are significant risk factors for heart disease and stroke.

Food additives like emulsifiers, artificial flavors, and colors can disrupt the gut microbiome, weaken the intestinal barrier, and potentially cause chronic inflammation. The long-term effects of consuming multiple additives are a growing concern.

Common examples include packaged snacks like chips and cookies, sweetened drinks, most breakfast cereals, many ready meals, fast food, and certain processed meats like hot dogs and chicken nuggets.